The program is designed to evaluate (1) the ability of certain steroids to affect the intake and pathophysiologic effects of dietary NaCl: at least two of these (19-OXO-DOC and 19-OIC-DOC) are adrenocortical intermediates in the adrenocortical synthesis of the potent adrenal hormone deoxycorticosterone. The first has been found to increase Na retention and the second to increase the consumption of NaCl and to cause kidney enlargement; (2) to evaluate the susceptibility of certain rat strains to the morbid effect of enhances, but relatively low intake of NaCl (as judged by mortality, impaired weight gain, hypertension, etc.) and (3) to study the influence of calcium blocking agents on the development, progress and effects of both acute and chronic hypertension using several different experimental models of hypertensive disease. The methodology includes measurement of blood pressure and heart rate serum and tissue electrolytes and hormones, microscopic examination of tissues, etc. The program is designed to increase knowledge of how sodium chloride influenced cardiovascular disease.